Pressure equalizer and method for reverse flow ventilated armature in power generator

An electromagnetic generator comprising:

• a rotating cylindrical rotor having an outer peripheral surface;
• a fan mounted on an axial end section of the rotor and aligned with an annular gas gap adjacent the outer peripheral surface of the rotor, wherein said fan draws cooling gas from the annular gap;
• an annular stator concentric to the rotor having stator core packets annularly arranged around the rotor and having an annular inner surface adjacent the gas gap, and radial stator ducts sandwiched between the stator core packets and open from the inner surface of the stator to an outer peripheral surface of the stator, wherein each duct has a cross-sectional duct area and a distribution of cross-sectional duct areas for the ducts is substantially non-uniform across the stator, and further said ducts include cooling gas inlets at the outer peripheral surface of the stator, and cooling gas outlets at the annular inner surface, wherein cooling gas enters the inlets, flows through the ducts and exits the outlets into the annular gap;
• a cooling gas plenum located radially outward of the stator open to the radial stator ducts, wherein the cooling gas enters an inlet to the plenum and flows through the plenum into the inlets of the cooling gas ducts;
• a heat exchanger having an exhaust outlet coupled to the inlet to the cooling gas plenum, wherein the cooling gas enters an inlet to the heat exchanger, through the heat exchanger, exits the exhaust outlet, and flows into the plenum;
• and
• a cooling gas conduit coupled to the inlet of the heat exchanger at a first end and open to the annular gas gap at a second end, such that the cooling gas is moved by the fan from the annular gap between the stator and rotor, and a cooling gas flow resistance between each inlet to the ducts and the second end of the conduit is substantially uniform for all ducts.

An electromagnetic generator comprising:

• a rotating cylindrical rotor having an outer peripheral surface;
• a fan mounted on an axial end section of the rotor and aligned with an annular gas gap adjacent the outer peripheral surface of the rotor, and said gas gap includes a gas exhaust upstream of the fan;
• an annular stator concentric to the rotor having stator core packets annularly arranged around the rotor and having an annular inner surface adjacent the gas gap, and radial stator ducts sandwiched between the stator core packets and open from the inner surface of the stator to an outer peripheral surface of the stator, wherein each duct has a cross-sectional duct area and a distribution of cross-sectional duct areas for the ducts is substantially non-uniform across the stator, wherein the cross-sectional duct area for a first stator duct is substantially greater that the cross-section duct area for a second stator duct, wherein the stator ducts are distributed along the stator at a predetermined frequency of ducts and the predetermined frequency of ducts is non-uniform along the stator, and cooling gas inlets to the ducts are at the outer peripheral surface of the stator, and cooling gas outlets to the ducts are at the annular inner surface, wherein a cooling gas flow resistance between the inlet to each duct and the gas exhaust from the gap is substantially uniform for all ducts;
• a cooling gas plenum located radially outward of the stator open to the radial stator ducts;
• a heat exchanger having an exhaust outlet coupled to an inlet to the cooling gas plenum;
• and
• a cooling gas conduit coupled to an inlet of the heat exchanger at a first end and open to the annular gas gap at a second end.